In electrical systems, the small-signal stability analysis method is usually applied to synchronous machines by using the Park representation (d, q-components). This paper presents the generalization of a different approach for this method, based on a, b, c phase variables. This approach is essential to software systems using phase variables as state variables and its generalization yields a small-signal stability analysis tool which is fully modular. Two test cases are presented to showcase the application of this approach to elements such as synchronous machines, automatic voltage regulator (AVR), power system stabilizer of type IEEE PSS2B, penstock, Francis turbine and speed regulator.